1. Field of the Invention
The present invention relates to a terahertz wave generation system, particularly to a terahertz wave generation system that generates terahertz wave by difference frequency generation being nonlinear optical effect.
2. Description of the Related Art
Conventionally, various kinds of research have been conducted regarding a method of performing spectroscopic analysis, imaging measurement or the like by using terahertz wave that is generated by difference frequency generation being nonlinear optical effect.
Meanwhile, it is necessary to illuminate terahertz wave on a subject of spectroscopic analysis or a subject of imaging measurement in order to use terahertz wave in spectroscopic analysis or imaging measurement. Generally, terahertz wave are transmitted to the above-described subjects by special propagation.
However, since such special propagation is poor in operability and transmission efficiency, the use of optical fibers having excellent operability and transmission efficiency is expected as means for transmitting terahertz wave to a subject to be illuminated, but existing optical fibers are made of a material having high absorption rate of terahertz frequency region, so that they cannot be used in transmitting terahertz wave.
With such a background, although the use of new photonic crystal fibers were attempted in recent years, they are still on a development stage and have not been practically used yet.